Alarm clock and switch



June 10, 1947. D. L. BOHMAN ALARM CLOCK AND SWITCH Filed March '7, 1946 2 Sheets-Sheet 1 David L. Bohma n Hi6 Abtorneg.

JUIIC 10, 1947. BQHMAN 2,421,986

ALARM CLOCK AND SWITCH 2 Sheets-Sheet. 2

Filed March 7, 1946 I'nv enter David L. Bohman,

Hi5 AUb or neg.

- view of an alarm clock me Patented June It), 1947 2,421,986 ALARM CLOCK AND SWITCH David L. Bohman,

Telechron Inc.,

Ashland, Mala, aslignor to a corporation of Mali Application March 7, 1946, Serial No. 652,727 9 Claims. (Cl. 58-19) My invention relates to an alarm clock of the type which may operate both an audible and a silent alarm or two consecutive alarms of different volume or character, one of which is controlled by a switch.

My invention is applied to a clock driven by an alternating current motor and uses a vibrator buzzer operated by the motor field as one of the alarms. A switch is provided for operating the other alarm which may be any one of a variety of electrically operated alarms, such as a flashing lamp, a radio receiver, a fan, a vibrator, etc.

An important feature of my invention is'provisions for controlling these alarms independently of each other so that either or both may be a used as desired. Another important feature of my invention is provisions whereby the alarm switch may be turned on automatically at a selected time and turned off manually at any desired time thereafter. The control mechanism has provisions for turning on and of! the alarm circuit permanently or back to the latter reconditioning the mechanism for automatic operation. when the two types of alarms are both used the time period between the automatic operations of such alarms may be made adjustable to suit different people and situations.

The features of my invention which are besame manual switch from the front of the clock.

consecutively,

iieved to be novel and patentabie will be pointed out in the claims appended hereto. For a better understanding of my invention, reference is made in the description to the accompanying drawings in which Fig. 1 represents a perspective invention; Fig. 2 shows details of the vibrator alarm shutoff; Fig. 3 indicates the manner in which an automatic switch operating cam fol-- lower is flexed sideways by its cam and prevents automatic lifting of the cam Figs. 4 to 8, inclusive, indicate different positions of the automatic and manual switch operating g. 9 represents a face view of the clock; and Fig. 10 one way the time period between the successive operations of the two adjustable.

Referring to Fig. 1, I represents the magnetic field core and 2 the energizing coil of a self-startciock motor of the general type containing the rotor through which the shaft 4 drives the clock thrcilsh gear I.

embodying my lever and blocking of makin automatic Patent No.

Theminutehandlandits cs 2 hollow shaft I are driven hour through back gears. cated at O. The hour hand ii are driven from the through back gears,

at one revolution per one of which is indi- II and its hollow shaft minute hand shaft l one of which is indicated at II on a shaft ll. The back gear train 0 includes a friction clutch at I! to facilitate setting the hands of the clock by means of the setting shaft 2! from the rear of the clock. The alarm cam shaft it and the alarm setting dia1 it are both driven from shaft I through a friction clutch i1 and gears It, is, and 10, preferably at one revolution in twelve hours. Hence the alarm setting dial it is driven at the same rate and in the same direction as the hour hand III. A short pointer Inn. on the hour hand shaft ii cooperates with the alarm setting dial II to indicate on said dial the time at which the alarm is set to operate. The alarm cam shaft l5 and alarm setting dial may be set means of the alarm setting shaft 22 accessible when the minute and hour hands are set by turning shaft ii, the alarm setting dial it and alarm cam shaft II are also set accordingly so as ordinarily fixed time relation with the clock hands but may be set relative set shaft 22. On shaft II are the audible alarm cam 23 and the switch operating cam 24. The audible alarm cam 23 has a depression 2'! therein into which a cam rider extending from armature 26 drops when the depression 25 is opposite the cam rider extension. Twenty-six (26) is a resilient magnetic armature member rigidly secured to the core i through a strap 21 at the left end of coil 1 and extending past the coil to the vicinity of a magnetic part 18 secured to the motor core at the right of the coil 2. The armature member is thus in flux shunting relation to the motor armature air gap of the core, which air gap is occupied by a reduced portion of gear casing 3 as shown in Patent No. 1,495,936, and when the coil 2' is energized by alternating current,

cam 23. the armature and hence does not No. 2, The cam 28 rotates clockwise and is so shaped independently of the clock hands bytostayina' to clock time through the alarm as to raise the armature 24 out of the depression after a suitable alarm period as the clock runs following such automatic audible alarm operation. The armature 22 can also be raised out of the cam depression to silence the alarm prior to the time it would otherwise be raised by the cam, or it can be prevented from dropping in the cam depression entirely by means of a resilient hook member 29, extending under the riahthand free end of armature 24, when such hook member is raised by pushing in on th alarm setting shaft 22.

such that when the shaft 22 and cone 29 are moved to the rear, hook 29 and armature 29 are raised to silent position as indicated in Fig. 2. As illustrated in Fig. ward position, which will allow the audible alarm to operate at the time for which set, indicated by hand Illa on dial it. When in the latter position, the double cone member 20 acts as a detent' against a rear bearing plate 2i for shaft 22. In-

the last-mentioned position, the gear 22 on shaft 22 is preferably demeshed from gear I! to avoid unnecessary wear, since when such gears are meshed, shaft 22 is driven with the clockwork.

From the above description it is seen that the audible alarm may be used or not as desired, and when used, may be shut off manually as soon as desired, after it is started automatically and if not shut off manually, will be shut oii' automatically after a suitable time interval. This automatic operation will occur at a selected time as determined by the setting. The manual shutoif parts are designed to be firmly held in the positions to which adjusted. The setting and shutoff control are both actuated from the same thumb piece 22a on shaft 22 from the front of the clock The other cam 24 on shaft i5 has a rectangularly shaped depression 22 therein and cooperates lever 24 pivoted at 25 to participate in the operation of a switch mechanism consisting of three resiliently mounted contacts 36, 31, and 38. A manually rotatable shaft 29 also participates in the operation of this switch mechanism and has three positions established by a detent at 40 and marked on the front of the clock as Auto (meaning automatic), Off" and On. A thumb piece 29a on the front end of shaft 39, by means of which shaft 39 is positioned, has an arrow thereon which points to and incicates the rotary position of this manual switch operating shaft. Thus in the position represented in Fig. 1, the arrow points to Auto meaning Automatic, and when in this position. the cam 24 and lever 24 have automatic control of the closing of the lower contact 38 of the switch to the extent that such parts have control. When button 39a is turned to Off position. all switch contacts are open, cam lever 24 is held in a raised position, and cam 24 and lever 34 do not exercise any control. When button 29a is turned to On" position, the switch contacts 36 and 31 are closed 1, the shaft 22 is in its for-" and the cam 24 and lever 24 again have closing control of the lower contact. Due to the circuit connections generaib used, it is immaterial whether contact 22 be closed or not in the On position of the switch.

An important feature of this Joint automatic and manual control of theswitch is the use of cam follower lever 24, which is made of sufliciently thin material as to be resilient in a sidewise direction, and a cam follower part 44 set at an angle to the rectangular slot 22 in the cam 24 so that the part 4i may be pushed out of the cam slot 22 in a sidewise direction as the cam rotates past part 4i without lifting the lever- 24. may likewise move into the slot from the side without lifting of the lever 24, In case the cam 24 is rotating clockwise as viewed in Fig. 1 when the part 4! is in slot 22, as will be the case following an automatic operation with the clock in normal operation, the part 4i will be pushed out of slot 22 on the rear side of the cam 24 as represented in full lines in Fig. 3. In case the cam follower part 4i is in slot 22 when the cam is set forward in the same direction to change the alarm time, the part 4i will likewise be pushed out on operation so far as this cam having the cam blocked by reason of cam follower part 4i being located in the rectangular slot having essentially radial drop and rise sides. The angular bend of part 4i may be in either direction. As shown, it has a bend of about 45 degrees to the front of lever 34. Instead, it could have a bend of about 45 degrees to the rear. The only diflerence would be in the direction it pushes out of the slot for a given direction of rotation of the cam. It is to be noted in Fig. 1 that the cam lever 24 is undercut at 42 adJacent part 4|, so that the lever part will not engage with the periphery of the cam and prevent the sidewise disengagement of part 4i from the slot 22 in either direction. To prevent cam lever 24 dropping down to a position where it might not clear the periphery of the cam 24 in such sidewise movement, the lever has an upper hook projection 42 which engages with a stationary post 44 to limit the downward movement of lever 24. It is seen that so far as the automatic operation of lever 24 is concerned, by the clock operated cam 24, the cam will permit the cam lever to move from raised to lowered position but will not move it from lowered to raised for this is that one purpose of the device is to turn on a radio program at a selected time automatically when the cam lever is lowered by closing certain contacts of the switch, and to avoid having the program interrupted by subsequent automatic opening of the switchcontacts, The switching operation performed automatically by a lowering of lever 34 may be reversed manually when desired by manual turning of switch operating shaft 39 from automatic to of! position, and such operation also lifts the cam lever 24 from its lowered to raised position.

The pivoted end of lever 24 carries a piece of insulating material having upper and lower sector-shaped arms 49 and 48 which move with the lever. The upper arm 4| cooperates with the resilient lower contact 22 of the switch. This contact is biased upwardly so as to normally engage the center or intermediate contact 31, and the purpose of arm 45 is to press contact 38 downward to hold contacts 31 and 38 open when the cam lever 34 is. in the raised position as shown in Fig. 1. When the lever 34 is lowered by reason of part 41 dropping into cam slot 33, arm 4 is retracted from contact 38 and allows it to close on contact 31. The lower arm 46 which is moved with lever 34 is positioned to engage with a finger 41 on the switch shaft 33 when the shaft is moved to or is in Off position. Such engagement positions the lever 34 to raised position, moves it to such position if it is not already in such position, and prevents its automatic movement from raised position. When switch shaft 39 is in the automatic position shown in Fig. l, finger 41 is above arm 46 as shown in Figs. 4 and 5 whether the lever 34 be in the raised position, Fig. 4, or in the lowered position, Fig. 5.

Fig. 6 represents the position of finger 41 with shaft 39 in Off position and it will be evident that finger 41 in moving from "Au position. Fig. 5, to Off position, Fig. 6, will raise lever 34 and open switch contacts 31 and 38. The lever 34 is thus raised whether the cam follower part 4! be in the slot 33 of the cam 24 or be shoved to one side of the cam as represented in Fig. 3. This comprises the means for manually lifting the cam lever 34 following an automatic lowering operation. When in Off" position, Fig. 6, the rounded end of finger 41 engages the rounded end of arm 46 so that finger 41 may be rotated in either direction past arm 46, lever 34 turning on its pivot to allow this. When the switch shaft 39 is in On" position, is below arm 46 in either the raised or lowered position of the latter as indicated in Figs. 7 and 8.

The upper resilient contact 36 is normally biased upwardly so as not to contact with the intermediate contact 31. has a finger 48 extending downward therefrom, which is positioned to engage with the wedge surface 49 on the rear of a finger 53 secured on switch shaft 39, so that when the shaft is turned to On position as represented in Figs. '1 and 8, wedge surface 49 pushes rearwardly on finger 48 which bends contact arm 36 downward, so that its forward end contact engages with contact 31 as represented in Figs. '1 and 8. It is evident that the movement of contact 36 is controlled manually and never automatically. The resilient contact members are all supported by an insulated support at 5! a sufficient distance from their free contact ends to permit of the switching movements described, and provisions are made at the insulated support to connect the contact members to the circuits to be controlled. The contacts may be connected in a variety of ways to circuits and devices to be controlled. Either the upper or lower set or both sets of contacts may the simple expedient of leaving a contact which is not to be used disconnected. or the corresponding contact may be omitted from the mechanism entirely without interfering with the proper functioning of the remaining parts. 5

One circuit connecting arrangement which may be used is represented in Fig. 1 where 52 represents a circuit plug outlet secured on and accessible from the rear of the clock and into which some electrical appliance to be controlled may be plugged. One side of such outlet is connected by wire 52a to one side of the same source 53 as is used to supply the electric clock motor field 2. The other side of outlet 52 is connected through its finger 41 However, contact 36 wire 54 to upper terminal 36 of the switch, and the center contact 31 of the switch is connected through wire 55 to the opposite side of source 53, so that when contacts 36 and 31 are closed, as they will be in the "On" position of switch shaft 39, the plug 52 is energized. Another connection from the lower side of plug 52 back to the source of supply which parallels the connection just described is available through wire 56, a contactor 51, wire 58, the lower contact 38 of the clock switch and through center contact 31 and wire 55 when contacts 31 and 38 are closed in response to an automatic clock operation. The contactor at 51 is of the intermittent opening and closing type operated by a bimetallic thermal strip 53 and a heater coil 66 which is connected at one end through wires 52a. and 6| to one side of source 53 and has its other end 62 connected to the bimetal strip 59. Hence the heater coil is energized whenever strip 59 is connected to the other side of source 53 through clock contacts 36 and 31 or through contacts 31 and 38 and 51. Contacts 51 are normally closed when the heater coil 66 is not energized. Hence with clock contacts 36 and 31 open and contacts 31 and 38 closed, the thermal contact device will function to intermittently open and close the contacts at 51 and its own circuit and the circuit of any appliance plugged into socket 52. When the bimetal strip 59 is heated by coil 69, it bends upward to open contacts 51 and then cools to close such contacts. The intermittent thermal contactor is generally used when the circuit just described is used as an alarm circuit by plugging into socket 52 a lamp or a vibrator. A fiashing lamp is desirable as an alarm to awaken deaf persons. It will be understood that as thus used the switch shaft 39 will be turned to the automatic position and the alarm time set to close switch contacts 31 and 33 at the time desired to awaken or otherwise notify the person so using the apparatus. Except for the power supply leads 53, the wiring described is preferably contained and concealed in the clock case.

In case the intermittent feature is not desired in the automatic alarm circuit, it may be omitted or simply short clrcuited by connecting the upper and lower clock contacts 36 and 38 together either permanently or as by a switch 63. As thus connected the switch clock is ideal for use with a radio receiver, as the same device may be used to turn the radio 'on and off manually as desired, as well as to turn it on automatically at a set time. The apparatus will not interrupt a se lected radio program automatically, but a person may cut it of! when desired by turning the button 390 to "Off and when subsequently turned back to automatic from either the "Off" or On" position, the apparatus conditions itself for automatic operation by lifting cam lever 34. When cam lever 34 has been pushed to one side of the cam 24 and is thus lifted, it springs back to normal position over the upper cam surface as soon as it is lifted above such surface, and as soon as finger 41 moves away from arm 46,.th'e cam lever comes to rest with the cam follower part 41 resting on the periphery of the cam.

When connected as shown in Fig. l, the heater coil 66 will be continuously energized when the switch shaft 39 is turned to On" position and the plug 5| is energized. This does no harm. It simply holds the contacts at 51 open. Also as wired, the opening and closing of contacts 31 and 36 has no effect when the switch is turned to "On" position. As shown in Fig. 9, the alarm asaaoee 7 button 21a and the switch operating button Ila are accessible from the front of the clock and are conveniently positioned at the 3 and 9 o'clock positions of the clock dial. It is evident from the foregoing description that the automatic audible buzzer alarm 28 associated with the field of the motor may be permanently cut oil or temporarily cut off after being turned on automatically before it would otherwise be turned oi! by cam 23 by pushing in on the alarm set button 22a, and that both this alarm and the automatic electric alarm circuit may be set to operate at selected times by turning the button 22a when in the pulled-out position. It is to be noted that the shutting off of the buzzer alarm does not interfere with any automatic switching operation to be performed by the lever 34 and cam 24.

cally closed through contacts 31 and 38 may be used or not independently of the buzzer alarm by turning button 39a from "Auto to "Off" and the circuit in question may be turned on and oil as desired by turning button 38a between 011" and Oii'." When subsequently turned to Auto, 39 is repositioned for automatic operation. The circuit which is closed automatically does not open automatically. Thus when this circuit is used to turn on a radio receiver at some selected time, the radio program is not interrupted in the middle of a desired program by automatic clock operation but may be turned on" when desired manually.

Notwithstanding the independence between the two alarm release operating mechanisms, they are so designed as to be used together by first turning on a gentle alarm such as a flashing lamp more persistent buzzer alarm. To this end the two earns 23 and 24 are so rotatively positioned on their common shaft II that as the shaft is turned clockwise by the operation of the clock, cam follower ll of switch lever II will drop into slot 33 of its cam. say, ten minutes before the cam follower projection of armature 20 drops into slot 25 of cam 23. As thus used the procedure may be as follows: Upon retiring, the person using the clock sets both alarms to automatic and time sets the alarm to operate at the desired awakening time. When such time arrives. the electric circuit will be turned on automatically, thereby turning on a radio program, for example. If this awakens the sleeper within a short time interval, he may push in on button 22a so that the audible buzzer alarm will not operate. If the sleeper is not aroused by the first alarm, the buzzer alarm will sound in a short period of time to sound until shut off manu- The electric alarm circuit may be opened manually at the will of the operator either before or at any time after the time the buzzer alarm would sound if permitted to do so. The cam shaft I preferably makes one revolution in 12 hours rather than 24 hours. since the device is intended to be used throughout the day and evening for automatically turning on selected radio programs or other electrical appliances at selected times with the buzzer alarm shut on, and a 12-hour cam may be set more accurately than a 24-hour cam.

The period of time between automatic operation of the switch and the turning on of the 8 buzzer alarm is primarily determined by the relative-rotative positions of the cam slots II and 88 on shaft II, and this is ordinarily set factory for, say, a ten-minute period. in some instances, the person owning will not change the time of drop-oi! at cam II because the cam follower projection of armature 2| is angles to the face of its cam. is shown means for taking advantage of this situation for varylngthe period of time between the operation of the two automatic alarms. The cam shaft ii is rotatively mounted in clock plates, one of which is shown at N, to permit slight endwise movement of shaft I 5 but not enough to interfere with the meshing of gears l8 and 32 when they are intended to mesh. AdJacent the periphery of cam 23 some distance removed from the cam follower part of armature 20 is a shaft 65 screw-threaded through clock plate It and endwise position of shaft As positioned in Fig. 10, the sloping cam follower H is about to drop off into the slot 83 in its cam 24 as the cam rotates in the direction of the arrow thereon. It is evident that with the cam 24 in the rotative position indicated, the cam follower I will drop in slot ll if the cam be moved axially to the left about two-thirds of a period of several minutes. erabb' arranged so that the switch lever ll operates automatically from about 5 to 30 minutes before the buzzer armature 20 operates with the approximate exact period adjustable to suit the user. This range of adjustability can be inboth cam followers at oblique but reverse angles to their cams. The apparatus may of course be arranged to lelect which type of alarm will operate first and/to adjust the period between their automatic operations. The recess 88 has rounded shoulders so as to guide the cam 23 into the races without difficulty when the cam slot 2| passes this point. The shaft ll may be screwed endwise into place after the clockwork and cam shaft have been instructions assembled by rotating cam 23 so that its slot 25 is in alignment with shaft 85. I

It will be evident that moving the normal position of cam lever 34 sidewise will accomplish the same purpose as endwise movement of cam shaft l5. Either of these expedients is generally easier to accomplish than attempting to rotate the cams relative to each other after the clock is assembled, both from the point of manufacture and for the user. The rear of the clock will carry about shaft 85 to indicate which way to turn the shaft to lengthen and shorten the adjustable time period in question. This adjustable feature may be omitted without interfering with the remaining structure or its operation.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An alarm clock combination comprising a clock, audible alarm means, an electric alarm circuit including a switch, a pair of automatic release mechanisms, both operated by said clock one for controlling operation of said audible alarm and the other for closing said switch, common means for adjusting said release mechanisms for the purpose of determining the time when the audible alarm will sound and the time the switch will be closed automatically, means for at will preventing the sounding of the audible alarm when it would otherwise sound, and means for at will preventing the closing of the switch when it would otherwise close in response to automatic clock operation, said two preventing means being independent of each other such that either or both the audible alarm and the switch may thus be operated automatically or prevented from operation by the clock at the times set for such operations.

' 2. An alarm clock combination comprising a clock, electric alarm circuit including a switch, a pair of automatic release mechanisms, both operated by said clock one for starting and stopping the operation of said audible alarm and the other for closing said switch, common means for adiusting said release mechanisms to determine the times when they will perform their automatic operations, manual means for at will preventing the automatic sounding of the audible alarm when it would otherwise sound and to stop its operation when sounding, manual means for at will preventing the automatic closing of said switch when it would otherwise close and to open the switch when closed, said two manual preventing means being independent of each other whereby either or both the audible alarm and the switch may thus be operated automatically, or prevented from operating automatically when they would otherwise so operate, and whereby the audible alarm may be silenced when sounding and the switch opened whenplosed independently of each other.

3. An alarm clock combination comprising a clock, an audible alarm, an alarm circuit including a switch, a pair of release mechanisms both operated automatically in response to the operation of said clock at predetermined adjustable times, one release mechanism controlling the automatic starting and stopping of said audible alarm and the other release mechanism controlling the automatic closing of said switch and being designed to prevent the automatic opening operation of the switch, and manual means for opening said switch and reconditioning the switch closing automatic release mechanism for subsequent automatic switch closing operation.

4. A switch and clock combination comprising a clock, a circuit including a switch having first and second positions, a rotary cam continuously driven by said clock, a pivoted cam lever riding on said cam as a cam follower for operating said switch and having first and second positions corresponding to the similar designated positions of said switch, said cam having which the contacting portion of said cam follower moves to cause the automatic operation of said when and lever from said first to second positions, said depression being shaped so as to prevent the cam follower from riding out of said depression in a direction to return the lever and switch from said second to first'positions, said cam lever being flexible in a direction at right angles to its switch operating movement and having a cam follower surface shaped so as to be pushed out of said cam depression in said right angular direction by said cam whereby the cam follower is prevented from blocking the continued rotation of said cam, and manual means for returning said lever and switch to their first positions.

5. A switch and clock combination comprising a clock, a switch therein having first and second operating positions, a cam follower lever for operating said switch between said positions and having first and second positions corresponding to the like designated positions of said switch, a rotary disk-shaped cam continuously driven by said clock and on the periphery of which the cam follower portion of said lever is adapted to ride, said cam containing a slot with substantially radial edges such that the cam follower will drop therein automatically in moving the lever from first to second positions but will not ride radially out of said slot to move the lever from second to first positions in response to the rotation of said cam, said lever being flexible in the axial direction of said cam and having a cam follower portion set at an angle of the order of 45 degrees to the axial direction of the cam so as to be flexed and pushed out of the depression sidewise by the rotation of the cam. and manual means for returning said lever from the second position, either before or after being flexed sidewise, to the first position in an unflexed condition.

6. An alarm clock combination comprising a clock, an audible alarm, anelectric alarm circuit including a switch, a pair of automatic release means operated by said clock one for releasing the audible alarm to permit it to sound, and the other for closing said switch, means for adjusting the time of day at which said automatic operations will be performed, and other means for adjusting the time period between said two automatic operations.

7. An alarm clock combination comprising a clock, a pair of rotary disk-shaped cams mounted on the same shaft and driven by said clock, a pair of cam followers bearing against said cams, means operated by said cam followers for controlling the automatic operations of separate alarms, means for adjusting the rotary position of said cam shaft relative to the clock for determining the time of day the automatic alarm operations will be performed. said cam followers being set at diilerent angles across their respective cams, and means for adjusting the relative positions of said cam shaft and cam followers in a direction endwise of the shaft whereby the time period between the automatic alarm operations performed by said cam followers may be adiusted.

a depression into 8.- In combination with a clock, an alarm circuit including a first switch, movable means operated by said clock at a predetermined adjustable time for automatically closing said switch, said means being incapable of automatically opening said switch. manual means associated with said switch and having first, second, and third positions, the first position permitting the automatic closing operation of said switch, the second position preventing the automatic closing operation of said switch, a second normally open switch in parallel relation with said first switch in said circuit, the third position of said manual means closing said second switch, switch position indicating means for at will moving said manual means back and forth between first and second and between second and third positions, the movement of said last-mentioned means from first or third position to second position opening the first switch if closed and repositionin the automatic means for a subsequent automatic switch closing operation if not in such position.

9. An alarm clock combination comprising a clock, an audible alarm, first and second switches for controlling a circuit, automatic means operated by said clock for starting and stopping said audible alarm and for closing the first switch, movable manual means accessible at the front of said clock for adjusting said automatic means to cause said automatic operations to occur at predetermined desired times and at will to permit or prevent the sounding of said audible alarm 12 without interfering with said automatic switch closing operation, another movable manual means accessible at the front of said clock to, at will, permit or prevent the automatic closing operation oi said first switch without interfering with said automatic audible alarm operations and to, at will, open said first switch it closed and recondition its automatic closing means for a subsequent automatic closing operation 11' not in such condition, said last-mentioned manual and close the second switch and having the same position for the open condition of the second switch as that for preventing automatic closing operation of the first 5 switch.

DAVID L BOHMAN.

I REFERENCES CITED The following references are of record in the 20 file of this patent:

UNITED STATES PA'I'ENTS Number Name Date 2,099,547 Varley Nov, 16, 1937 25 1,860,159 Porter May 24, 1932 1,701,399 Vickery Feb. 5, 1929 1,430,852 Roesch Oct. 3, 1922 FOREIGN PATENTS 30 Number Country Date 333,388 Great Britain Aug. 14, 1930 

